It came down to the Cougars packing Swiss Army Knifes against a Top 10 team that brought heavy rifles.

The game was an entertaining 21-21 tie going into the fourth quarter. It looked like it would go down to the wire. But BYU's highly touted defense faced talented receivers and pass protection it could not crack for the first time this season. The Cougar defenders could not make enough plays to save BYU's offense.

So, since BYU knocked off Oklahoma in Dallas in 2009, it is still hunting for a victory over a ranked opponent.

The Cougars will next face No. 7-ranked Notre Dame in South Bend, Ind. The Fighting Irish rallied to beat Stanford 20-13 in overtime Saturday.

Brigham Young Cougars wide receiver Cody Hoffman (2) watches the end of the game from the bench during the Oregon State game in Provo Saturday, Oct. 13, 2012. (Jeffrey D. Allred, Deseret News)

During a big fourth quarter in LaVell Edwards Stadium that started with both teams tied at 21, OSU simply made huge plays. BYU could not match it in style or execution. OSU's QB could throw a mile on target; BYU's could not.

"It was dead even at halftime," said BYU coach Bronco Mendenhall, "and I thought it would go like that to the very end. We were trying to match score for score and then we didn't."

BYU senior quarterback Riley Nelson made a gallant comeback from suffering fractured vertebrae in his battered back. He made plays. He executed the option with precision. He hit receivers in the zones OSU limited him to, though he had tight ends drop passes. As is his custom, he ran with guts and glory to convert big third downs.

When this game was on the line, it was OSU backup quarterback Cody Vaz (20-of-32, 332 yards, three TDs) who had his hands on a big-play offense with nasty weaponry. And he used it to perfection.

Nelson took four sacks and said he tried to play safe to protect himself in the second half, but thinking about it afterwards, he should have ran more to keep drives alive.

With 11 minutes to play in the game and OSU up 28-21, Nelson engineered an inspired drive down the field. It was as pretty as any this season. He did what a leader and captain is supposed to do to tie up the game and put pressure on OSU.

That is, until he had a first-and-goal at OSU's 10.

Brigham Young Cougars wide receiver Cody Hoffman (2) watches the end of the game from the bench during the Oregon State game in Provo Saturday, Oct. 13, 2012. (Jeffrey D. Allred, Deseret News)

Nelson then overthrew Cody Hoffman on a short flare route along the line of scrimmage. On the next play, he led Hoffman too long in the end zone for an incompletion. On the next play, OSU sacked him and the Cougars settled for a Justin Sorensen field goal.

It was reminiscent of a first-half BYU drive that died at OSU's 30 when Nelson, surrounded by OSU defenders, targeted Hoffman, who was covered by three defenders. The play resulted in his first interception and a crucial lost drive. Like many times in his career, he'd have been better served to throw the ball away.

"Bounces didn't go our way," said Mendenhall. "Sometimes it happens and sometimes it is tied to execution. They made more plays than us today."

Nelson, who is not known for his accuracy deep, attempted 51 passes and completed 28. He had one touchdown pass to Devin Mahina and threw three interceptions.

Brigham Young Cougars sit on the bench at the end of the Oregon State game in Provo Saturday, Oct. 13, 2012. (Jeffrey D. Allred, Deseret News)

Nelson knows he had to match TDs with Vaz and Co.

It simply was out of reach.

"You have to answer with touchdowns when on the 10. When you are trading touchdowns for touchdowns, you have to answer with touchdowns," said Nelson.

But this was knifes vs. guns.

"Give them credit. We couldn't take the top off of them today," said Nelson, who told the post-game media throng how OSU's safeties took away the middle of the field and long post plays.

Concluded Nelson, "I have to do what the team needs to do for us to win the game. If that means making 5-yard passes, that's what I'll do. I have to keep completing and making first downs."

Brigham Young Cougars quarterback Riley Nelson (13) runs for a first down against Oregon State in Provo Saturday, Oct. 13, 2012. (Jeffrey D. Allred, Deseret News)

This is the first game BYU's offense didn't get a customary iron door from its defense. The Cougar defense had allowed just four touchdowns this season, but OSU managed five on Saturday. Bronco's guys couldn't get to Vaz quick or often enough.

This all leaves plenty for Mendenhall to write on the whiteboard this week heading to the home of the Golden Dome.

The Irish may lack OSU's firepower, but its defense is spiked rebar, led by LDS star Manti Te'o.